Process for clarifying liquids



I I give the following:

, suspended solids is conceived X result is that Patented Apr. 29, 1947PROCESS FOR ULABIFY G LIQUIDS Clarence Walter Wilson, Norco, CaliL,assignor to California Fruit Growers a corporation of CaliforniaApplication February 16, 1942, Serial No. 431,105

melee, Calif., No Drawing.

Exchange, Los Ane Claims- (cl. 09-105) This is aninvention of suspendedinsoluble solved materials from liquids, either for the purpose ofclarification of the liquid or for recovcry of the materials.

A difllculty encountered in many arts, for example, paper making, sugarmanufacture, wine making, and preparation of fruit insoluble solids orvarious kinds must be removed or recovered from aqueous solutions. Thesesolids are often of such a nomically be removed by the common processesof filtration, centriiugation, etc.

I have found that solids of many kinds may be precipitated orfiocculated from liquids by forming in the liquid a gel of an insolublepectate,

' and accordingly I will proceed to disclose specific examples of theapplication of this process to found in industry.

Re 21,077 describes the prepa various liquids My Patent No.

r'tion, from pectinous source materials, of soluble fibrous pectates ofthe alkali metals and amthe process involves an alkali extraction thepresent process, either pulp or the purified, extracted pectate may beused, as disclosed. Also, the better known noniibrous pectatesareuseful, though less effective.

As an example of the practice of my a To 1 liter of juice obtained fromsugar cane is added 0.4 g. of sodium pectate pulp, made and disperse inaccordance with the disclosure of Patent No. Re. 21,077. The' well mixedwith the liquid and Calcium ions naturally present with the pectate, andunder the conditions obtainins, the calcium pectate may form as acoextensive gel, which soon flocculates and precipitates. The gel may ormay not be detectable, and in some cases the first visible manifestationwill be the formation 0! the flocculent precipitate. I use the term gelto include jellies as well as gelatinous precipitates. Formation of theflocculent precipitate is believed to be due to syneresis of allowed tothe jelly first formed more or less throughout the juice are endraggeddown liquid. Suspended solids of the meshed in the. precipitate andthereby. degree to whichthe jelly forms coextensively with the wholebody of liquid. The insoluble residue ofthe-pectate pulp alsoprecipitates, and the net the sugar cane juice is bright and invention,

pulp dispersion is concerning the removal solids and certain dis-,-

iuices, is that nature that they may not ecoin the juice reactprecipitating cation found in or practice. Optimum colloidally dispersedsubstances also much reduced.

rather coarse suspended solids, in addition to a cloud which may persistindefinitely, if not removed. The orange juice treated as describedbelow was coarsely screened, and contained cloud and visible suspendedparticles.

Orange juice 315 Sugar syrup, 13 Brix 582 Sodium pectate, 5% sol 49Total 946 The orange juice and syrup were mixed, then the pectate soladded with stirring; The formation of large flocs occurred promptly, andthese ilocs settled out overnight, leaving a clear, supernatant juiceproduct. v

In the above case, sufilcient calcium was present in the juice to reactwith the pctate. A juice deficient in calcium was treated by supplyingcalcium, as follows:

Orange juice was first treated by dilution with twice its volume ofwater, To this dilute juice. was added a small amount of a sol ofpurified sodium pectate. No jellyingor flocculation was observed. To asecond sample of the dilute juice was added pectate sol was added tothis mixture, there formed a jelly which rapidly precipitated, carryingdown all suspended matters.

In the illustrations dealing with the tion of orange juice, theconcentration of 0.25%.- results with pectate added in such amounts as0.03% and 0.30%, based on weight of pectate to weight of treatedsolution.- These values are not limits, but are illustrative values, ofthe liquid belns treated. 4

Another variable is' found in the amount of added to theclarificaliquid. Calcium forms about 5.5% pectate. Best results probablyare found when the cation is in the neighborhood of combiningproportions with the pectate. Results of the process can be controlledby suitable modification of conditions uch as temperature, agitation,

strensth. and quantity of the .pectate sol. used.

fruit or vegetable the of pectate I have observedgood' of adequatecommercial course, vary with;

of calcium and acidity of the solution to clarified. An 1. Aprocess forthe clarification oi. liquids conexcess of soluble pectate will allow aportion of taining suspended solids and calcium ions which the sol toremain in the treated liquid. This may comprises adding thereto a sol ofa pectate of the tend to colloidally protect the system and intergroupconsisting of the alkali metals and ami'ere with efiicientprecipitation. Large excesses 6 monium, and subsequently separating theflocof either pectate or cation should be avoided culated solids fromthe liquid. where the highest degree of clarity in the liquid 2. Aprocess for clarifying plant juices conis desired, but is notparticularly important in taining suspended solids comprising mixing asol other applications, such as the treatment of white of a solublepectate with the juice, and allowing water where the main object isrecovery 01' the 10 the mixture to stand for a time to permit the mainpart of the solids, with clarity of the liquid formation of insolublepectates. a secondary consideration. A process for clarifying fruitJuices contain- Another illustrative use of myprocess is in the ingsuspended solids comprising mixing a sol recovery of fiber, fillers,etc., from the white of a pectate from the group consisting of alkaliwater which is generally a waste product from metal and ammonium withthe fruit juice, and paper manufacture. allowing the mixture to standfor. a time to per.-

One part of a 2.5% dispersion of pectate pulp mlt the formation ofinsoluble pectates. causes rapid and substantially complete precipi- '4.A process for clarifying sugar juice containtation oi the solidssuspended in 300 parts of mg suspended solids comprising mixing a sol 01white water from an ordinary paper-making a pectate from the groupconsisting of alkali process. These solids are generally lost becausemetal and ammonium with the sugar Juice, and they are filtrable onlywith difllculty and do not allowing the mixture to stand for a timesuiiinaturally settle out rapidly enough to make it cient to permit theformation of insoluble economical to treat the large volumes of liquidpectates and removing the flocculated solids from which are involved.After precipitation, the liqthe liquid.

uid may be separated from the solids in any de- 5. A process for therecovery of suspended sired manner. 9. g. by use of the widely knownsolids from white water comprising intimately Dorr thickener. mixing asol of a soluble pectate in the white In the beerand wine-makingindustries, subwater in an amount sumcient' to form an instances such assilicic acid and albumen are so soluble pectate gel in combination withelectroused for "fining. Pectates may be used here lytes presentin thewhite water. thereby causing with excellent results. They may also beused flocculation of the suspended solids, and reior clarification ofapple and grape juices. Apmoving the flocculated solids from the whiteple juice particularly is most attractive to the water.

consumer when bright and clear. Pectates, orig- 6. A process for therecovery of suspended mating as they do in fruits and vegetables.cansolids from liquids containing the same, comnot be considered foreignto food products of prising intimately mixing a sol of a soluble clumpectate, since calcium salts are universally .40 the liquid, therebycausing flocculation of the contained in natural products of the kindunder suspended solids, and removing the fiocculated consideration.Furthermore, calcium salts are solids from the liquid.

non-poisonous. Other polyvaient metals will CLARENCE WALTER WILSON.cause precipitation of gels from sols of pectates,

and may be used in my process as is calcium, it REFERENCES CITEDdesired' This 15 Particularly true 111 1101140 .The following referencesare 01 record in the applications of my process. With regard to the m oft atent: treatment of white water, electrolytes 01' various 6 his pmetals may normally be present and take part in UNITED STATES TS theprecipitating reaction. Number Name Date The principle of the inventioninvolve the 979,432 Hal-(1mm D8017 1910 formation in the liquid to beclarified or an in- 1,443,454 Booth Jam 30' 1923 soluble m tal pectateunder conditions such that 2,020,572 Plan; NW 12, 1935 the pectate willform substantially throughout 2,218,053 Schwabe et a1 "Oct. 15' 1940 theliquid as a gel which will rather quickly pre- 2,132,064 Wilson Oct. 4,1938 cipitate, carrying down (or up as the case may 2 7 Le Compte Feb.9, 1937 be) suspended solids. The nature of the pre- 1,838,949 Leo Dec.29' 1931 cipitate and thoroughness of precipitation may roREroNPA'I'ENTS the sol, and the quantity of sol added. I have 0 NumberCountry Date used sols containing pectate in proportions rang- 1,510 Brti h 1353 ing from 2% to 11%.

Agitation also affects results. Where utmost OTHER REFERENCES efilciencyis wanted. the pectate should be Geerligs, "Cane Sugar and Its Mfg, 2nded., thoroughly dispersed in the liquid under treati=3 London, 1924,page 163. merit before the precipitating reaction occurs. McIntosh,"Technology of Sugar," London,

n the above description, and in the appended 1916, page 99. claims, itwill be obvious from what has been said "Citrus Pectates-Properties,Manufacture, above that when pectate sols are referred to, and Uses," byW. E. Baler and C. W. Wilson, pub. those sols are aqueous in character.5 in Industrial and Eng. Chemistry, March 1941;

Having disclosed my invention. E claim: pages 287 to 291.

